Make issue template mandatory for github issue submission

[vijayank88]

@vvbandeira Can you please create issue template for OpenROAD github issue submission.

Example OpenLane follows https://github.com/The-OpenROAD-Project/OpenLane/issues/new?assignees=&labels=&template=bug_report.md&title= mandatory template issue submission.

Same way for OpenROAD user can fill OpenROAD commit currently using. If its an installation issue OS type information must be included. If its a flow issue ask them to attach .def .lef and flow.tcl for debugging the issue.